In order to suppress defects caused by a harmonic component included in a power-supply current, there is an international regulation regarding electronic devices that generate a harmonic current. In order to clear the regulation, there is employed a method of conducting power-supply short-circuit in a converter with AC or DC chopping to suppress a harmonic current included in a power-supply current.
As a converter that performs DC chopping, there is an interleaved converter that connects a plurality of chopper circuits in parallel, where these chopper circuits are respectively switched with a different switching phase, and ripples caused by switching are canceled out in an input current serving as a sum of currents flowing in each of the chopper circuits, thereby suppressing a harmonic current. In the interleaved converter with this system, there is a case where variations such as shifting of switching phases in the respective chopper circuits, switching-on times, and slopes at the time of switching on and off occur, so that currents flowing into the respective chopper circuits become nonequivalent, and thus suppressing effects of a harmonic current are decreased. In this connection, for example, there is disclosed a technique in which, based on respective values of currents that flow into a plurality of chopper circuits, off-times of respective switching elements in each of switching cycles for controlling these switching elements in a critical mode are predicted and, based on the prediction result, switching control is executed on the respective switching elements so that switching phases have a desired phase difference, thereby equalizing distribution of currents to the respective chopper circuits (for example, Patent Literature 1).